A user equipment (UE) detects a downlink (DL) control channel for carrying scheduling information about DL data transmission and accordingly receives DL data from an eNB. The UE generates acknowledgement/negative-acknowledgement (ACK/NACK) information indicating whether decoding of DL data is successful and transmits the ACK/NACK information to the eNB.
In a conventional wireless communication system, a resource used for transmission of ACK/NACK information may be determined from a DL control channel for carrying the DL scheduling information. In addition, in the conventional wireless communication system, the DL control channel is transmitted based on an antenna port of a cell-specific reference signal, and a UE detects and demodulates the DL control channel based on an estimated channel using an antenna port of the cell-specific reference signal.